fumarates and Necrosis

Topics: Adenine; Alanine; Animals; Anti-HIV Agents; Delayed-Action Preparations; Drug Implants; Female; Fumarates; HIV Infections; Humans; Inflammation; Macaca mulatta; Male; Necrosis; Polyurethanes; Rabbits; Subcutaneous Tissue; Tenofovir

Near-infrared photoimmunotherapy (NIR PIT) employs the photoabsorbing dye IR700 conjugated to antibodies specific for cell surface epidermal growth factor receptor (EGFR). NIR PIT has shown highly selective cytotoxicity in vitro and in vivo. Cell necrosis is thought to be the main mode of cytotoxicity based mainly on in vitro studies. To better understand the acute effects of NIR PIT, molecular imaging studies were performed to assess its cellular and vascular effects. In addition to in vitro studies for cytotoxicity of NIR PIT, the in vivo tumoricidal effects and hemodynamic changes induced by NIR PIT were evaluated by

Topics: Animals; Cell Line, Tumor; ErbB Receptors; Female; Fumarates; Hemodynamics; Humans; Immunotherapy; Infrared Rays; Magnetic Resonance Imaging; Mice; Mice, Nude; Necrosis; Oxidation-Reduction; Panitumumab; Photoacoustic Techniques; Photosensitizing Agents; Phototherapy; Skin Neoplasms; Xenograft Model Antitumor Assays

Dimethyl fumarate (DMF) is a newly approved drug for the treatment of relapsing forms of multiple sclerosis and relapsing-remitting multiple sclerosis. Here, we investigated the effects of DMF and its metabolites mono-methylfumarate (MMF and methanol) on different gastrointestinal cancer cell lines and the underlying molecular mechanisms involved.. Cell viability was measured by the MTT or CCK8 assay. Protein expressions were measured by Western blot analysis. LDH release, live- and dead-cell staining, intracellular GSH levels, and mitochondrial membrane potential were examined by using commercial kits.. DMF but not MMF induced cell necroptosis, as demonstrated by the pharmacological tool necrostatin-1, transmission electron microscopy, LDH and HMGB1 release in CT26 cells. The DMF-induced decrease in cellular GSH levels as well as cell viability and increase in reactive oxygen species (ROS) were inhibited by co-treatment with GSH and N-acetylcysteine (NAC) in CT26 cells. DMF activated JNK, p38 and ERK MAPKs in CT26 cells and JNK, p38 and ERK inhibitors partially reversed the DMF-induced decrease in cell viability. GSH or NAC treatment inhibited DMF-induced JNK, p38, and ERK activation in CT26 cells. DMF but not MMF increased autophagy responses in SGC-7901, HCT116, HT29 and CT26 cancer cells, but autophagy inhibition did not prevent the DMF-induced decrease in cell viability.. DMF but not its metabolite MMF induced necroptosis in colon cancer cells through a mechanism involving the depletion of GSH, an increase in ROS and activation of MAPKs.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Dimethyl Fumarate; Fumarates; Glutathione; HMGB1 Protein; Humans; L-Lactate Dehydrogenase; Maleates; MAP Kinase Signaling System; Membrane Potential, Mitochondrial; Methanol; Mice; Mitogen-Activated Protein Kinases; Necrosis; Reactive Oxygen Species

Methods for the simultaneous polarization of multiple 13C-enriched metabolites were developed to probe several enzymatic pathways and other physiologic properties in vivo, using a single intravenous bolus. A new method for polarization of 13C sodium bicarbonate suitable for use in patients was developed, and the co-polarization of 13C sodium bicarbonate and [1-(13)C] pyruvate in the same sample was achieved, resulting in high solution-state polarizations (15.7% and 17.6%, respectively) and long spin-lattice relaxation times (T1) (46.7 s and 47.7 s respectively at 3 T). Consistent with chemical shift anisotropy dominating the T1 relaxation of carbonyls, T1 values for 13C bicarbonate and [1-(13)C] pyruvate were even longer at 3 T (49.7s and 67.3s, respectively). Co-polarized 13C bicarbonate and [1-(13)C] pyruvate were injected into normal mice and a murine prostate tumor model at 3T. Rapid equilibration of injected hyperpolarized 13C sodium bicarbonate with 13C CO2 allowed calculation of pH on a voxel by voxel basis, and simultaneous assessment of pyruvate metabolism with cellular uptake and conversion of [1-(13)C] pyruvate to its metabolic products. Initial studies in a Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model demonstrated higher levels of hyperpolarized lactate and lower pH within tumor, relative to surrounding benign tissues and to the abdominal viscera of normal controls. There was no significant difference observed in the tumor lactate/pyruvate ratio obtained after the injection of co-polarized 13C bicarbonate and [1-(13)C] pyruvate or polarized [1-(13)C] pyruvate alone. The technique was extended to polarize four 13C labelled substrates potentially providing information on pH, metabolism, necrosis and perfusion, namely [1-(13)C]pyruvic acid, 13C sodium bicarbonate, [1,4-(13)C]fumaric acid, and 13C urea with high levels of solution polarization (17.5%, 10.3%, 15.6% and 11.6%, respectively) and spin-lattice relaxation values similar to those recorded for the individual metabolites. These studies demonstrated the feasibility of simultaneously measuring in vivo pH and tumor metabolism using nontoxic, endogenous species, and the potential to extend the multi-polarization approach to include up to four hyperpolarized probes providing multiple metabolic and physiologic measures in a single MR acquisition.

Topics: Animals; Biomarkers, Tumor; Enzymes; Fumarates; Gadolinium; Hydrogen-Ion Concentration; Indicators and Reagents; Injections, Intravenous; Isotope Labeling; Magnetic Resonance Spectroscopy; Male; Mice; Necrosis; Neoplasm Transplantation; Prostatic Neoplasms; Pyruvic Acid; Sodium Bicarbonate; Solubility; Urea

Dynamic nuclear polarization of (13)C-labeled cell substrates has been shown to massively increase their sensitivity to detection in NMR experiments. The sensitivity gain is sufficiently large that if these polarized molecules are injected intravenously, their spatial distribution and subsequent conversion into other cell metabolites can be imaged. We have used this method to image the conversion of fumarate to malate in a murine lymphoma tumor in vivo after i.v. injection of hyperpolarized [1,4-(13)C(2)]fumarate. In isolated lymphoma cells, the rate of labeled malate production was unaffected by coadministration of succinate, which competes with fumarate for transport into the cell. There was, however, a correlation with the percentage of cells that had lost plasma membrane integrity, suggesting that the production of labeled malate from fumarate is a sensitive marker of cellular necrosis. Twenty-four hours after treating implanted lymphoma tumors with etoposide, at which point there were significant levels of tumor cell necrosis, there was a 2.4-fold increase in hyperpolarized [1,4-(13)C(2)]malate production compared with the untreated tumors. Therefore, the formation of hyperpolarized (13)C-labeled malate from [1,4-(13)C(2)]fumarate appears to be a sensitive marker of tumor cell death in vivo and could be used to detect the early response of tumors to treatment. Given that fumarate is an endogenous molecule, this technique has the potential to be used clinically.

Topics: Animals; Antineoplastic Agents, Phytogenic; Biomarkers, Tumor; Carbon Isotopes; Etoposide; Female; Fumarate Hydratase; Fumarates; Lymphoma; Malates; Mice; Mice, Inbred C57BL; Necrosis; Neoplasm Transplantation; Neoplasms; Nuclear Magnetic Resonance, Biomolecular; Tissue Extracts; Treatment Outcome

Topics: Appetite Depressants; Dilatation; Fumarates; Humans; Hyperplasia; Hypertension, Pulmonary; Hypertrophy; Necrosis; Oxazoles; Pulmonary Artery